Refractive or reflective optical sights are used in a wide variety of applications to obtain increased magnification of a scene. In one common application, an optical sight is affixed to the upper side of the barrel of a rifle-type weapon used by a soldier. The user sights through the optical sight to acquire a target and aim the weapon toward the target to increase the likelihood of hitting the target with a projectile fired from the weapon.
A reticle is typically provided in the optical path of the optical sight. The reticle normally has reference markings or other information that aids the user in aiming the optical sight and thence the weapon toward the intended target. The reference markings usually include a cross hair or similar marking to indicate the bore sight of the weapon. The reference markings may also include elevation, windage, and other reference markings that assist in aiming the weapon.
The reticle may be illuminated by an artificial light source within the optical sight. The reticle illumination ensures that the reticle will be visible in lighting conditions including normal daylight, low-light ambient conditions, and, particularly for infrared and other optical sights to be used at night, in near-darkness conditions. If only ambient light is used to illuminate the reticle, the illumination may be uneven and undependable.
The illumination of the reticle ideally satisfies a number of requirements. The illumination of the reticle must not interfere with the observation of the scene being viewed, yet the reticle must stand out against the scene. The reticle output desirably is adjustable and has low power consumption. The reticle illumination must be relatively uniform over the entire reticle so that the entire exit pupil is filled. Existing illumination approaches do not fully meet these requirements.
There is a need for an approach for an improved optical sight having an illuminated reticle. The present invention fulfills this need, and further provides related advantages.